Properties are managed through the *.prp file and depending on the tools and flow are either in the Centlib.prp file or netlist.prp file. Both are managed by the Property Definition Editor launched either from Library Manager or the Tools menu in xDX Designer. Another file that manages migration between flows and/or different tools and versions is the map.cfg or mapnl.cfg file, this is used to transpose properties to the correct naming convention or remove erroneous properties. To fully understand this consult the documentation, it is too big a subject to discuss here. Also, please indicate which layout system you are using, Xpedition or PADS/PADS Professional as we can move this to the correct Community and provide flow specific feedback.